Phase transition of the Si(111)–Au surface from √3 ×√3 to 5×1 structure studied by means of the low-energy electron diffraction, Auger electron spectroscopy, and Rutherford backscattering spectroscopy techniques

Abstract

The changes of the Au coverage and the structure of the Si(111)–√3×√3-Au surface induced by isothermal annealing in the temperature range of 500–575 °C have been studied by means of low-energy electron diffraction (LEED), Auger electron spectroscopy, and Rutherford backscattering spectroscopy techniques. It is found that the Au coverages by RBS and AES at each temperature decay exponentially down to 0.75 ML, above which only the LEED pattern of √3×√3 spots is observed, and decay biexponentially from 0.75 ML and a mix of √3×√3 + 5×1 spots is observed down to 0.54 ML at 575 °C, 0.52 ML at 550 °C, and 0.61 ML at 530 °C, below which only the LEED pattern of 5×1 spots is observed. From analysis of the decay curves of Au coverages, it is determined that the activation energies for Au atoms to be dissolved from the √3×√3 structure and the 5×1 structure into the bulk and for phase transition of the Au/Si(111) surface from the √3×√3 to the 5×1 structure are 2.5±0.5, 2.8±1.0, and 1.6±0.4 eV, respectively. The process for the phase transition is discussed.